2
Features
Applications,
cont.
Research and
Development
The accuracy and versatility
of the modulation analyzer
make it a very useful labora-
tory instrument for charac-
terizing a wide variety of
devices and assemblies.
When used with a modulated
signal source the modulation
analyzer can make stimulus-
response measurements for
direct measurement of a
device’s effects on such
signals. Because of its wide
frequency range, it can
measure the performance
of both RF and IF assemblies.
Characterizing modulated
sources for sensitivity,
distortion, and incidentals,
and measuring the noise
performance of local
oscillators is also possible.
• Mixer and Amplifier com-
pression
• Local oscillator residual FM
• Modulator characterization
• Incidental AM or FM
• RF and IF characterization
Complete Signal
Characterization
The HP 8901A Modulation Analyzer
brings together in one instrument
several RF signal measurement
capabilities. It is more than just a
high quality modulation meter. It
accurately measures carrier fre-
quency and peak input power in
addition to completely characteriz-
ing modulation. This unique combi-
nation of capabilities makes the
HP 8901A Modulation Analyzer an
extremely powerful tool for analyz-
ing signals. In normal use it elimi-
nates the need to frequently connect
and disconnect several instruments,
such as counters and power meters.
The modulation analyzer is fully
programmable and can be used as
part of an automatic system to make
all these measurements under
remote control.
Single Key Measurements
The HP 8901A Modulation Analyzer
features easy to use controls. In
automatic operation, all major func-
tions are selected by pushing a
single key. No manual tuning or
range selection is needed. The modu-
lation analyzer automatically tunes
to the input signal, adjusts for proper
signal level, selects the appropriate
measurement range, makes the mea-
surement, and displays the result.
For certain measurements manual
operation may be more desirable.
When selecting a specific signal in
the presence of others or for special
applications, the operator can easily
use the modulation analyzer’s key-
board to set any or all measurement
parameters. Functions not selected
manually remain in automatic mode.
This greatly increases the modulation
analyzer’s versatility.
High Performance
The HP 8901A Modulation Analyzer
offers a significant advancement in
modulation measurements. Modula-
tion depth and deviation are mea-
sured with unprecedented 1 percent
accuracy. To complement this capa-
bility, optional calibrators with 0.1
percent depth or deviation accuracy
can be included in the analyzer.
A significant improvement has also
been made in the area of residual
noise. The extremely low internal
noise of the modulation analyzer
makes possible residual AM and FM
measurements even on very stable
signals. Accurate measurement of
signals with small incidental AM
or FM modulation are now easily
performed. Residual AM in a 50 Hz
to 3 kHz bandwidth is <0.02 percent,
and residual FM in the same band-
width is <8 Hz at 1300 MHz
decreasing to <1 Hz below
100 MHz.